I built the Tubelab SE with 45 triodes and a SS rectifier. All the tubes were installed on the chassis. Be careful if you do the same thing:

Install the stopper resistors close to the grid pin. 3.3k was enough for the 5842 and the I didn't change the 100R of the 45.

I had to add separate power supply and transformer for the 45 filaments to avoid noise (soft start using LT1084).

Since I had a little hum, more filtering was necessary (few hundreds microfarads) for the B+ supply. I had in mind to use stacked Zener diodes with a HV MOSFET for regulation and slow start: it works well.